Geology Of Ore Deposits Research Articles

Computer-assisted user access to science information in an academic institute

Questions about the creation and functioning of a computer-assisted information system (CAIS) that includes an integrated databank on scientific research in geology are examined. The system serves the staff of scientific organizations with the use of multi-aspect request processing. Using the example of the CAIS for the scientific research of the Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry of the RAS (IGEM RAS), the basics of the interaction of the system infrastructure components, their composition, methodological principles of formation and functioning of a unified information communication system are presented. In particular, the CAIS carries out the spatial integration of documentographic and factographic heterogeneous data according to geographic information system technology. The composition, structure, and functions of the specialized linguistic support of the system are described. The methodological fundamentals for the solution of the task of ore deposit prediction in the CAIS are used as an example.

Geochemical comparison of kimberlites from the Siberian and East European platforms: Problems of genesis and spatial zoning

239. 1156 Kimberlites from two Russian provinces, the East European (EEP) and Siberian (SP) platforms, were compared in terms of their traceelement composition and the ages of emplacement and mantle enrichment (Ndmodel ages). Previous comparisons were focused on geological, geomorphological, and mineralogical data (1), whereas our works are mainly underlain by isotopegeochemical studies, which provide insight into key problems of kimberlite petrology. In order to exclude methodical errors, kimberlites were analyzed in several known laboratories (Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry; Institute of Precambrian Geology and Geochronology and the Geological Institute of the Russian Academy of Sciences; and the Institute of Mineralogy, Geochemistry, and Crystal Chemistry of Rare Elements) using a common scheme described in (2). Numerous varieties of kimberlites distinguished by statistical analyses of a great body of available data significantly complicated their comparison. There� fore, in this work, we limited ourselves to comparison on the basis of the TiO 2 content in kimberlites. It was taken into account that TiO 2 is the typomorphic ele� ment of all potassic ultrabasic rocks, being an indica� tor of the depth of melt formation. Three petrological types of kimberlites of EEP and SP. It was recently found that rocks previously ascribed to a single kimberlite clan are characterized by broad compositional variations. In 1985, two groups differing in Sr and Nd isotope composition were distinguished among the South Africa kimber� lites (3); two new kimberlite types enriched in trace elements were later recognized at Koidu (Sierra Leone, Africa) and Aries in Australia (4). In 1995, Mitchell (5) proposed to restrict the application of the term kimberlites to the rocks that were previously clas� sified as Group I kimberlites of South Africa. Since the composition of rocks and minerals of Group II kim� berlites of South Africa are transitional to lamproites (the presence of REErich phosphates, perovskite, as well potassium richterite in differentiated varieties), these kimberlites were referred to as orangeites. In the pastt decade, the number of kimberlite types increased: special attention was drawn to a new type of diamondiferous kimberlites which was referred to by us as the Zolotitsa type (2) after the Zolititsa occur� rence in the EEP, whose rocks are depleted in Ti and trace elements (Fig. 1). At the same time, Siberian geologists described geochemically similar (including low TiO 2 content) diamondiferous kimberlites in the Nakyn field (Yakutia) and Slave craton (Canada) and proposed to consider them as anomalous kimberlites. Since the TiO2 content is an indication of pressure, the low Ti content in the "Zolotitsa" and "anomalous" kimberlites indicates their highpressure origin. Kimberlites are subdivided into three petrologi�

A LINEAR-RING STRUCTURE MODEL FOR ORE DEPOSIT LOCATION IN THE LAOCHANG SILVER-LEAD ORE ZONE AND ITS APPLICATION TO THE PROGNOSIS OF CONCEALED DEPOSITS

Based on an interpretation of linear and ring structures and the extraction of alteration information from TM imagines,in combination with ore deposit geology and geochemical data,the authors formulated a linear-ring structure model for ore deposit location in the Laochang ore zone according to the theory of remote sensing deposit geology.Under the background of the regional NNW-trending tectonic belt,the cross overlapping ringed structure is formed by the superimposition of the NS-trending axial Nanlao ring reflecting the Hercynian volcanic depression and a series of EW-trending axial lenticular structures reflecting the Yanshanian-Himalayan concealed intermediate-acid rock bodies.The anomalous hue zones controlled by NNW-striking lines show the alteration information.The overlapping segments are places favorable for mineralization.

Geology and Situation of Ore Deposits in the Region of the Iimori Mine.

Geology and Situation of Ore Deposits in the Region of the Iimori Mine.

Description and crystal structure of a new mineral – plimerite, ZnFe3+4(PO4)3(OH)5 – the Zn-analogue of rockbridgeite and frondelite, from Broken Hill, New South Wales, Australia

Plimerite, ideally Zn (PO4)3(OH)5, is a new mineral from the Block 14 Opencut, Broken Hill, New SouthWales. It occurs as pale-green to dark-olive-green, almost black, acicular to prismatic and bladed crystals up to 0.5 mm long and as hemispherical aggregates of radiating acicular crystals up to 3 mm across. Crystals are elongated along [001] and the principal form observed is {100} with minor {010} and {001}. The mineral is associated with hinsdalite-plumbogummite, pyromorphite, libethenite, brochantite, malachite, tsumebite and strengite. Plimerite is translucent with a pale-greyish-green streak and a vitreous lustre. It shows an excellent cleavage parallel to {100} and {010} and distinct cleavage parallel to {001}. It is brittle, has an uneven fracture, a Mohs’ hardness of 3.5–4, D(meas.) = 3.67(5) g/cm3 and D(calc.) = 3.62 g/cm3 (for the empirical formula). Optically, it is biaxial negative with α = 1.756(5), β = 1.764(4), γ = 1.767(4) and 2V(calc.) of –63º; pleochroism is X pale-greenish-brown, Y pale-brown, Z pale-bluish-green; absorption Z > X > Y; optical orientation XYZ = cab. Plimerite is orthorhombic, space group Bbmm, unit-cell parameters: a = 13.865(3) Å, b = 16.798(3) Å, c = 5.151(10) Å, V = 1187.0(4) Å3 (single-crystal data) and Z = 4. Strongest lines in the X-ray powder diffraction pattern are [d (A˚ ), I, hkl]: 4.638, (50), (111); 3.388, (50), (041); 3.369, (55), (131); 3.168, (100), (132); 2.753, (60), (115); 2.575, (90), (200); 2.414, (75), (220); 2.400, (50), (221); 1.957, (40), (225). Electron microprobe analysis yielded (wt.%): PbO 0.36, CaO 0.17, ZnO 20.17, MnO 0.02, Fe2O3 29.82, FeO 2.98, Al2O3 4.48, P2O5 32.37, As2O5 0.09, H2O (calc) 6.84, total 97.30 (Fe3+/Fe2+ ratio determined by Mössbauer spectroscopy). The empirical formula calculated on the basis of 17 oxygens is Ca0.02Pb0.01Zn1.68Al0.60P3.09As0.01O17.00H5.15. The crystal structure was solved by direct methods and refined to an R1 index of 6.41% for 1332 observed reflections from single-crystal X-ray diffraction data (Mo-Kα radiation, CCD area detector). The structure of plimerite is isotypic with that of rockbridgeite and is based on face-sharing trimers of (Mϕ6) octahedra which link by sharing edges to form chains, that extend in the b-direction. Chains link to clusters comprising pairs of corner-sharing (Mϕ6) octahedra that link to PO4 tetrahedra forming sheets parallel to (001). The sheets link via octahedra and tetrahedra corners into a heteropolyhedral framework structure. The mineral name honours Professor Ian Plimer for his contributions to the study of the geology of ore deposits.

The 16th International Geological Congress, Washington, 1933

In 1933, the International Geological Congress (IGC) returned to the United States of America (USA) for its sixteenth meeting, forty-two years after the 5 th IGC convened in Washington. The Geological Society of America and the U.S. Geological Survey (USGS) supplied the major part of the required extra-registration funding after the effects of the Great Depression influenced the 72 nd U.S. Congress not to do so. A reported 1,182 persons or organizations, representing fifty-four countries, registered for the 16 th IGC and thirty-four countries sent 141 official delegates. Of the total number of registrants, 665 actually attended the meeting; 500 came from the USA; and fifteen had participated in the 5 th IGC. The 16 th Meeting convened in the U.S. Chamber of Commerce Building from 22 to 29 July. The eighteen half-day scientific sections-orogenesis (four), major divisions of the Paleozoic (three), miscellaneous (three), batholiths and related intrusives (two), arid-region geomorphic processes and products (one), fossil man and contemporary faunas (one), geology of copper and other ore deposits (one), geology of petroleum (one), measuring geologic time (one), and zonal relations of metalliferous deposits (one)-included 166 papers, of which fifty (including several of the key contributions) appeared only by title. The Geological Society of Washington, the National Academy of Sciences, and the U.S. Bureau of Mines hosted or contributed to evening presentations or receptions. Twenty-eight of the 16 th IGC's thirty new guidebooks and one new USGS Bulletin aided eight premeeting, seven during-meeting, and four post-meeting field trips of local, regional, or national scope. The remaining two new guidebooks outlined the USA's structural geology and its stratigraphic nomenclature. The 16 th IGC published a two-volume monograph on the world's copper resources (1935) and a two-volume report of its proceedings (1936).

Sources of material for massive sulfide deposits in the Urals: Evidence from the high-precision MC-ICP-MS isotope analysis of Pb in galena

This work reports the results of one of the pioneer investigation of the Pb isotope geochemistry based on modern high-precision multichannel mass spectrometry with inductively coupled plasma (MC-ICP-MS). We studied the main mineral and age groups of massive sulfide deposits in the Urals: superlarge Gai deposit (~9 Mt); large deposits, such as Sibai (Cu + Zn, ~3 Mt), Uchaly (~7 Mt), and Saf’yanov (~2 Mt); and eight medium and small deposits. The lead isotopic compositions of these deposits were studied in 54 galena samples. According to Albarede [1], the MC-ICP-MS method has opened “a new era in isotope geochemistry,” particularly in the study of the Pb isotopic composition [2, 3]. Until recently, the method of thermoionization mass spectrometry (TIMS) dominated in this field. The overwhelming majority of Pb isotope data reported in the world during the last 50 years is based on the TIMS measurement of 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 208 Pb/ 204 Pb ratios with an error of 0.1‐0.2% or more. Application of the MC-ICP-MS method decreased the error by 5‐ 10 times. Therefore, it has become possible to investigate minor local and regional variations in the Pb isotopic composition, decrease significantly (from ± 35 to ± 4 Ma) the analytical error of the model Pb‐Pb age calculation, and unravel “short” correlation trends of the isotopic characteristics of Pb. We have developed and applied a special MC-ICPMS version based on the NEPTUNE (ThermoFinnigan) device at the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (Moscow). The method consists in the high-precision isotopic analysis of Pb from Tl-doped solutions and the normalization of all current Pb isotope data relative to the

Selected ore deposits of Brazil

This series of papers on a variety of ore deposits in Brazil is the outgrowth of the “First Brazilian Symposium on Metallogeny” held in Gramado, Rio Grande do Sul, in May 2005. The selection of papers mirrors quite well the range of commodities and fascinating diversity of ore deposit types Brazil has to offer. The thematic issue starts with a paper by Monteiro et al. who use detailed petrography to establish a consistent paragenetic sequence of alteration and mineralization throughout the Sossego iron–oxide–copper–gold (IOCG) deposits in the giant Carajas Mineral Province. Combined with stable isotope data, it allows the authors to constrain the spatial and temporal zoning of hydrothermal alteration and mineralization. They conclude that the Pista-SequerinhoBaiano and Sossego-Curral ore bodies formed at a deep and high structural level of an IOCG system, respectively. Significantly, the copper–gold mineralization was late in the alteration history and broadly synchronous in both ore bodies. Another contribution to the ore deposit geology of the Carajas Mineral Province is by Dreher et al. who use new geologic, fluid inclusion and stable isotope data to establish that the Igarape Bahia Cu–Au deposit displays both characteristic syngenetic VHMS and epigenetic IOCG style geological features. This controversial paper provides evidence via recent B isotope data on tourmaline that there is the distinct possibility of an involvement of a marine evaporitic source in the hydrothermal system of Igarape Bahia. The authors carefully evaluate evidence for both genetic models and correctly agree that more detailed work needs to be conducted to resolve this fascinating genetic conundrum. Souza Neto et al. provide an overview of W–Au skarns in the Serido mobile belt in the Borborema Province in northeast Brazil. Special emphasis is put on the reduced Bonfim Au–Bi–Te skarn deposit. The majority of skarns in the Serido mobile belt are oxidized tungsten skarns even though the Itajubatiba and Bonfim gold-bearing skarns display reduced features, such as pyrrhotite as predominant sulfide, garnet with high almandine plus spessartite component, and elevated gold content. PIXE data revealed that significant amounts of F (up to 9,490 ppm) are present in prograde titanite, and retrograde clinozoisite–zoisite and gold-related epidote, suggesting significant F activity in the skarn forming hydrothermal fluids. Beurlen et al. in a second paper on mineralization in the Borborema Province use Nb–Ta–(Ti–Sn)–oxide mineral chemistry as tracer of rare-element granitic pegmatite fractionation in the pegmatite-rich Borborema Province. The Borborema Pegmatite Province, with over 750 registered mineralized rare-element granitic pegmatites, is a historically important tantalum province and is currently well known for top-quality gems, such as the Paraiba Elbaite. Detailed electron microprobe analyses of pegmatite Miner Deposita (2008) 43:127–128 DOI 10.1007/s00126-007-0174-y

F. I. Wolfson: Scientist, teacher, and patriot

Following a brief biography, the scientific, administrative, and educational activity of F.I. Wolfson is described. Also considered are the principal lines of his research: the study of the structures of ore fields and deposits, the geology of uranium deposits, the theory of hydrothermal ore formation, and the history of the study of ore deposits. The immense contribution made by Wolfson to the development of the mineral resources of the country (uranium, nonferrous metals, etc.) is shown and the continuing relevance of his theoretical and methodological works in the field of geology of ore deposits is emphasized.

The ideas and scientific works of F.I. Wolfson and their current implications for the geology of uranium deposits

The outstanding contribution of Professor F.I. Wolfson to the origination and development of Russian science and practice in the field of geology of uranium deposits is emphasized. Under his guidance, a team of highly skilled specialists on uranium deposits was gathered at the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences, in Moscow. Owing to their efforts, all significant uranium deposits in the former Soviet Union and socialist bloc countries have been studied comprehensively. A theory of uranium ore formation was developed on this basis, and elaborated practical recommendations promoted the creation in the Soviet Union of the world’s largest uranium resource sources. Today, Wolfson’s ideas and works are widely used in planning and carrying out complex investigations at operating uranium deposits and in new promising uranium districts.

The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling

The paleoproterozoic Ghanaian province: Geodynamic model and ore controls, including regional stress modeling

K-Ar dating of quaternary volcanics: Methodology and interpretation of results

The K-Ar method and its modifications play a unique role in the geochronology of young volcanic rocks, which has important fundamental and economic aspects. This method provides an opportunity for dating Quaternary rocks, from the oldest (1–2 Ma) to the most recent ones (<30 ka). This paper discusses physical and geochemical prerequisites for the use of the K-Ar method in the solution of this problem. The key factor providing favorable proportions of radiogenic and nonradiogenic 40Ar for the K-Ar system in volcanic rocks is the low solubility of argon (0.n–0.0n ppb) in silicate melts and crystallizing rocks and minerals. The sources and controlling factors of errors in the K-Ar dating of young rocks were evaluated in detail. The main analytical problem in the K-Ar dating of young rocks is concerned with the conditions and methods of measurements of very low (0.0n–0.00n ppb) contents of radiogenic 40Ar accompanied by much higher (by a factor of 3–10 or even more) contents of nonradiogenic 40Ar. The main stages in the development of the K-Ar method in Russia and other countries that provided a solution to this problem are described. We describe the analytical mass spectrometer system and method designed in the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences, which allowed us to carry out for the first time in Russia systematic studies on the geochronology of Quaternary volcanics up to late Pleistocene-Holocene age. The main characteristics of the method are the absolute sensitivity of measurements (5 × 10−3 A/Torr) and background signal levels for argon isotopes (3 × 10−3 ng 40Ar and 1 × 10−5 ng 36Ar). The problems of excess radiogenic argon and variations in the initial 40Ar/36Ar ratio in young volcanics are discussed. The results of an investigation of the distribution of K-Ar isotopes among various constituents of young volcanics and the corresponding approach to the choice of material (geochronometer) for analysis are presented. This approach is illustrated by the example of geochronological results for three volcanic centers of the Caucasus differing in the time of occurrence and duration of the active phase: Elbrus, Samsari, and Aragats. A tentative regional time scale was proposed for Neogene-Quaternary magmatic events. This scale generalized the available data for the Greater and Lesser Caucasus and embraces the period from the late Miocene (8.5 Ma) to the late Neopleistocene-Holocene (<35 ka). An interesting feature of the young magmatism of the Caucasus is the synchronous occurrence of distinctive types of volcanic activity in particular volcanic areas. An important prognostic aspect related to the proposed time scale of the young magmatism of the Caucasus is the evidence that the most recent stage of volcanic activity, the youngest occurrences of which were dated at a few thousands to tens of thousands of years, is not yet finished.

Information System Using Remote Aerospace Archive

A system of interaction and exchange of information on natural sciences between the Center of Aerospace Information and the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry of the Russian Academy of Sciences was prototyped between 1999 and 2002 by a team of researchers and experts. It is based on the latest advances in communications and geoinformatics and intended for significant strengthening of the scientific and technical support of the fundamental studies in the field of Earth sciences. In contrast to the current practice of this country, not only catalogs of aerospace photos are transmitted through the remote links, but also full digital images. Metadata offer a convenient graphic interface to the user. A mathematical model was developed for estimating the throughput of the Internet link connecting the aerospace archive with the local computer network of the Institute of Geology. The calculations performed enabled one to establish the necessary characteristics and construct a fiber-optic link for the prototyped information system.

The geology and genesis of high-grade hematite iron ore deposits

This paper presents a first summary of results of an ongoing study, started some two years ago, of high-grade iron ore deposits in South Africa, India and Brazil, including a comparison with the rather well-studied deposits of the Hamersley Province in Australia. Large, high-grade hematite iron ore bodies hosted by Precambrian banded iron formations are the world's most important source of iron ore. Despite their great economic importance, the origin of these deposits has remained rather enigmatic. Results of preliminary investigations into the geological setting, petrography and geochemistry of BIF-hosted high-grade hematite iron ore deposits in South Africa, India, Western Australia and Brazil reveal distinct similarities, suggest ing a very similar mode of hydrothermal and supergene-modified hydrothermal origin for most BIF-hosted highgrade hematite ore deposits. Differences between the deposits of this type are largely the result of varying intensities of supergene modification in Late Cretaceous to Tertiary times. Notable exceptions are the deposits in the Griqualand West region of South Africa, including the giant Sishen deposit, that are regarded to be of ancient supergene origin.

Exploration and mining ventures in Peru

During Colonial times (1535-1821) gold was produced mainly from placers, silver from the Hualgayoc, Cerro de Pasco, Castrovirreyna, and Cailloma districts, and mercury from the Huancavelica district. After a long period of stagnation following the wars for independence, Peru9s mining industry started to prosper during the turn of the century, furthered by Peruvian and foreign mining geologists, engineers, and entrepreneurs. Particularly successful was the mining development within the area of influence of Cerro de Pasco Copper Corporation9s La Oroya smelter in central Peru.After World War II Peru9s mineral industry blossomed under the Mining Code of 1950 due primarily to sizeable foreign investments, but also due to the development of the local medium-sized mining industry. Extensive exploration led to the discovery and development of many ore deposits, especially the porphyry copper deposits of southern Peru and a number of vein, skarn, metasomatic replacement, and hydrothermal sedimentary deposits of precious and base metals.Peru9s mining development has slowed drastically since 1968 as a consequence of nationalization of foreign enterprises, more restrictive mining regulations, and terrorism. Despite these setbacks, significant contributions have been made to the geologic knowledge of the country by foreign government missions, academicians, and consultants, as well as by Peruvian geologists. These studies have documented the geology and geochemistry of many ore deposits and highlighted the potential for additional discoveries and development of diverse mineral resources using modern techniques.

Prospect over and around a strange hill

It is pointed out that a strange hill and its immediate surroundings should always be regarded as a target for prospectors. Strangely, this fact has generally not been emphasised by 20th. century writers of books, etc., on mineral exploration and the geology of ore-deposits. For the purpose of this paper a hill is regarded as strange if one or more of the following criteria apply to it:- (i) it dominates a comparatively flat terrain; (ii) it differs significantly in shape from its neighbours; (iii) it has an unusual geologic setting; (iv) it stands out from the general terrain because ofits plan-shape; (v) it possesses an anomalous ornamentation; (vi) it possesses anomalous geochemical and/or geophysical characteristics. (These are not discussed in the text.) Finally, it is suggested that a law should be established that for the sake of brevity should read 'If you know of a strange hill prospect there.

Diffusion, phase equilibria and partitioning experiments in the NiFeRu system

The diffusion coefficient for Ru in Ni ( D Ni Ru) was determined by the thin-film diffusion method in the temperature range of 1073 to 1673 K and is given by the expression: D Ru Ni(cm 2 sec−)=5.0 (±0.7)·10 −3 exp[−2.3(±0.1)·10 12 erg mole−/ RT] where R is the gas constant and T is the temperature in K. Phase boundaries and tie lines in a NiFeRu-rich system were determined at 1273, 1073 and 873 K. A wide miscibility gap is present at each temperature, separating a close-packed hexagonal ϵRuFe phase from a face-centered cubic γNiFe phase, The partitioning behavior of Pt and Ir between phases in a NiFeRu-rich system and V between phases in a NiFeO-rich system was determined at 873 K. Pt partitions preferentially into the γNiFe phase, whereas Ir prefers the ϵRuFe phase. V partitions strongly into Fe oxides relative to γNiFe. The experimental results have applications in the fields of meteoritics, ore-deposit geology and materials science.

The Geology of Ore Deposit. John M. Guilbert , Charles F. Park Jr.

Previous articleNext article No AccessReviewsThe Geology of Ore Deposit. John M. Guilbert , Charles F. Park Jr. J. Barry MaynardJ. Barry Maynard Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 96, Number 1Jan., 1988 Article DOIhttps://doi.org/10.1086/629200 Views: 8Total views on this site Copyright 1988 The University of ChicagoPDF download Crossref reports no articles citing this article.

The orientation of bedding, veins and joints in core — a new method and case history

A new technique is described for the orientation of bedding, joints and veins in diamond drill core taken from rocks in which a cleavage is developed. The geological and mathematical basis of the method is explained and a computer program suitable for IBM compatible microcomputers is included. A case history of its use during a gold exploration program at the Dolaucothi gold mines (Ogofau) in Dyfed, Wales is also presented which highlights its use in structural modelling and interpretation, geotechnical studies and in ore deposit geology.

Radioelements in Standard Samples Pertaining to Magmatic Rocks Included in the Single System of the USSR State Standard Samples (According to Gamma‐Spectrometric Data)

Results of the study of 18 standard rock samples developed in the Institute of Geology of ore deposits, petrography, mineralogy and geochemistry (IGEM) and included in the Single System of the USSR State Standard Samples are given in the present paper. The content of radioelements was determined by the method of low background gamma‐spectrometry on the basis of comparison with international standard rock samples.